Lactose Mother Liquor Stream Valorisation Using an Effective Electrodialytic Process.

Area of Science:

• Chemical Engineering
• Environmental Science
• Food Science

Background:

• Dairy industry generates lactose-rich waste streams (lactose mother liquor - LML).
• Valorization of LML is essential for sustainable dairy processing and resource recovery.
• Lactose is a valuable milk sugar with diverse industrial applications.

Purpose of the Study:

• Optimize downstream processes for lactose crystallization from LML.
• Investigate electrodialysis (ED) performance for LML pre-treatment and desalination.
• Evaluate the impact of ED on ion-exchange membranes and process efficiency.

Main Methods:

• Diluting LML to 25% total solids to address hydraulic challenges.
• Applying two levels of electrical conductivity reduction (70% and 90%) via ED.
• Measuring ED performance parameters: ash transfer rate (J), specific capacity (C), and specific electric energy consumption (E).

Main Results:

• Higher desalination levels (90% vs 70%) increased energy consumption by 50% and reduced specific capacity by 40%.
• Anion exchange membranes showed a 12.8% decrease in resistance post-treatment.
• Cation exchange membranes' resistance remained largely unchanged; no alkaline earth metal deposition was observed.

Conclusions:

• Electrodialysis is effective for pre-treating and desalinating LML for lactose recovery.
• Process optimization involves balancing desalination degree with energy consumption and capacity.
• ED treatment shows minimal adverse effects on ion-exchange membranes, suggesting process viability.